Thermal Ablation System

ABSTRACT

A thermal ablation system comprises a fluid handling unit receiving fluid from a fluid source at a first pressure, the fluid handling unit including a heater heating the fluid to a desired temperature and a pump and an introducer including a sheath which, when in an operative position, is received within a hollow organ, the sheath including a delivery lumen introducing fluid heated by the heater to the hollow organ and a return lumen withdrawing fluid from the hollow organ and returning the withdrawn fluid to the console via a return lumen, wherein the pump increases a pressure of the fluid between the fluid source and the delivery lumen of the introducer.

PRIORITY CLAIM

This application claims the priority to the U.S. Provisional ApplicationSer. No. 60/987,913, entitled “THERMAL ABLATION SYSTEM,” filed on Nov.14, 2007. The specification of the above-identified application isincorporated herewith by reference.

BACKGROUND

Menorrhagia, excessive uterine bleeding during a prolonged menstrualperiod, has been attributed to disorders of the endometrial lining ofthe uterus. While a hysterectomy provides a definitive treatment formenorrhagia, physicians and patients may choose less invasive proceduresto reduce side effects, prolonged hospital stays and procedural andpost-operative discomfort.

Generally, the less invasive procedures employ electrical energy (e.g.,RF energy), heat (e.g., laser) or cryogenic treatment. However, theseprocedures typically rely on direct visualization of the uterus and anexperienced operator applying the energy, heat, etc. to selectedportions of the uterine lining. Alternatively, the entire inner liningof the uterus may be treated by conduction uterine ablation, i.e.,circulating a heated fluid through the uterus. In other similarprocedures, the heated fluid may be contained within a balloon whilecirculating through the uterus.

SUMMARY OF THE INVENTION

The present invention relates to a thermal ablation system comprising afluid handling unit receiving fluid from a fluid source at a firstpressure, the fluid handling unit including a heater heating the fluidto a desired temperature and a pump and an introducer including a sheathwhich, when in an operative position, is received within a hollow organ,the sheath including a delivery lumen introducing fluid heated by theheater to the hollow organ and a return lumen withdrawing fluid from thehollow organ and returning the withdrawn fluid to the console via areturn lumen, wherein the pump increases a pressure of the fluid betweenthe fluid source and the delivery lumen of the introducer.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows an exemplary embodiment of a thermal ablation systemaccording to the present invention;

FIG. 2 shows a frontal view of an exemplary embodiment of a console of athermal ablation system according to the present invention;

FIG. 3 shows an exploded view of an exemplary embodiment of a console ofa thermal ablation system according to the present invention;

FIG. 4 shows an exploded view of an exemplary embodiment of a right sidecomponent of a console of a thermal ablation system according to thepresent invention;

FIG. 5 shows an exploded view of an exemplary embodiment of a valveassembly for a console of a thermal ablation system according to thepresent invention;

FIG. 6 shows an exploded view of an exemplary embodiment of a front sidecomponent of a console of a thermal ablation system according to thepresent invention;

FIG. 7 shows an exploded view of an exemplary embodiment of a chassis ofa console of a thermal ablation system according to the presentinvention;

FIG. 8 shows an outer view of an exemplary embodiment of a cassette of athermal ablation system according to the present invention;

FIG. 9 shows an inner view of an exemplary embodiment of a cassette of athermal ablation system according to the present invention;

FIG. 10 shows an exemplary embodiment of an introducer of a thermalablation system according to the present invention;

FIG. 11 shows an exemplary embodiment of an open loop fluid flow path ofa thermal ablation system according to the present invention;

FIG. 12 shows an exemplary embodiment of a closed loop fluid flow pathof a thermal ablation system according to the present invention;

FIG. 13 shows an exemplary embodiment of fluid flow through a heatingchamber in a cassette according to the present invention;

FIG. 14 shows an exemplary embodiment of an impeller of a thermalablation system according to the present invention;

FIG. 15 shows an exemplary embodiment of an impeller of a thermalablation system according to the present invention; and

FIG. 16 shows an exemplary embodiment of a cervical seal of a thermalablation system according to the present invention.

DETAILED DESCRIPTION

The present invention may be further understood with reference to thefollowing description and to the appended drawings, wherein likeelements are referred to with the same reference numerals. The presentinvention relates to systems, methods and apparatuses for thermallyablating tissue, e.g., tissue lining an inner surface of a hollow organ.In particular, the present invention relates to devices for ablating theendometrial lining of the uterus. However, those of skill in the artwill understand that the present invention, or components thereof, maybe utilized in prostate treatment (microwave or cyroablation) systems,irrigation systems or other procedure which require infusion of fluidinto a patient.

FIG. 1 shows an exemplary embodiment of a thermal ablation system 2according to the present invention. Generally, the system 2 includes aconsole 4 having a pole 6 extending from an upper portion thereof and astand 8 coupled to a lower portion thereof. The pole 6 preferablyextends to a predetermined height above the console 4 so that anintravenous (IV) bag (not shown) hung therefrom will supply fluid to theconsole 4 at a desired pressure. The IV bag contains fluid such assaline that will be heated and circulated through the uterus to ablatethe endometrial lining. During the ablation procedure, an operator(e.g., physician, nurse, etc.) may be required to substitute the IV bagfor IV bags with other fluids depending on stage of the ablationprocedure. For example, prior to the procedure an anesthetic fluid maybe circulated through the uterus to numb the surgical site.Additionally, after the endometrial lining has been ablated, ananalgesic and/or infection preventative solution may be circulatedthrough the uterus. In another exemplary embodiment, IV bags for anyfluids required during the procedure may be concurrently attached to thepole 6 with the height of the pole 6 determining the pressure at whichthese fluids will be supplied to the console 4.

A height of the stand 8 on which a fluid supply bag will be hung ispreferably variable using a height-adjusting mechanism to control apressure of fluid reaching the treatment site as will be describedbelow. The height-adjusting mechanism may be a pneumatic lift, africtional lock, etc., allowing the operator to manually adjust of theheight of the stand 8. In another exemplary embodiment, theheight-adjusting mechanism may comprise an automated height adjustmentmechanism controlled by user actuation or automatically by electroniccircuitry in the console 4 based on sensor data, etc.

In the exemplary embodiment, the stand 8 is provided with a mobile base10 (e.g., locking wheels) so that the system 2 is easily moveable andsteerable. However, those of skill in the art will understand that thebase 10 may be static or that electronic control and movement of thesystem 2 may also be implemented.

As shown in FIG. 2, the console 4 according to the present inventioncomprises a housing 10 encasing electronic circuitry and providing auser interface 12 for displaying content (e.g., instructions, proceduraldata, warnings, etc.) and receiving user input. The user interface 12may comprise a display screen 14 (e.g., LCD) and a keypad 16 forsubmitting input to the console 4. Those of skill in the art willunderstand that the keypad 16 may be replaced or augmented by dials,switches, a touch screen (or the screen 14 may be made responsive totactile input) or any other controls operable by the operator of thesystem 2. In one exemplary embodiment, a disposable overlay (not shown)may be applied over the user interface 12. For example, if the displayscreen 14 is a touch screen and the operator intermittently providesinput to the user interface 12 by touching the display screen 14, anoverlay may be used to prevent the display screen 14 from becomingdamaged or obscured by fluid.

The housing 10 may further include a handle 18 for steering the system 5and a slot 26 receiving a cassette 28, which is described below. In theexemplary embodiment, the handle 18 includes an alignment beam activator20 which, when pressed, causes a light beam (e.g., laser light) to beemitted from a beam exit port 24 on the console 4. As would beunderstood by those skilled in the art, the light beam may preferably beoriented horizontally so that, as the height of the console 4 isadjusted using the height adjusting mechanism on the stand 8 until thebeam is positioned on a desired portion of the patient's anatomy, theoperator will know that the console 4 is in a desired position relativeto the uterus. Making the console 4 a desired height off the floorrelative to the uterus (e.g., the same height) ensures that a pressurewith which the fluid is circulated in the uterus does not exceed apredetermined value. Those of skill in the art will understand that theactivator 20 may be disposed adjacent to the user interface 12 and/orthe keypad 16 may be positioned on the handle 18. The housing 10preferably also includes a hook 22 for hanging a drainage bag (notshown) from the console 4. After ablating the endometrial lining, thefluid is discharged into the drainage bag.

FIG. 3 shows internal components of an exemplary console 4 according tothe present invention. The housing 10 of the console 4 includes a frontside 30, a rear side 32, a left side 34 and a right side 36. Those ofskill in the art will understand that the housing 10 may be comprised ofany number of components in any number of geometrical relationships toone another and that the terms front, rear, left and right arerelational terms used only to describe the exemplary embodiment of theconsole 4. A chassis 38 inside the housing 10 acts as an attachmentpoint for the sides 30, 32, 34, 36 and supports various electricalcomponents of the console 4. In this embodiment, the front side 30includes circuitry powering the user interface 12 and the beam activator20, while the rear side 32 provides an input for a power source (e.g.,line voltage). However, in other exemplary embodiments, the system 2 maybe powered by an on-board battery. The left side 34 generally comprisesa vented wall which allows air heated during operation of the electriccomponents of the console 4 to be expelled therefrom, while the rightside 36 includes components that interface with the cassette 28.

FIG. 4 shows an exemplary embodiment of the right side 36 of the console4 which includes components for interfacing with the cassette 28. Thecassette interface generally includes a valve arrangement 40 and a motorarrangement 42. The valve arrangement 40 includes one or more valves 46(e.g., pinch valves) which engage outer surfaces of flexible tubeswithin the cassette 28 via openings in a rigid housing thereof toselectively open and close the tubes without contacting fluids flowingtherethrough. As shown in FIG. 5, an exemplary valve assembly 50 is apinch valve. However, those of skill in the art will understand that thefunctions of the valves 46 may be performed by any device(s) configuredto selectively open and close the tubes in the cassette 28 withoutcontacting fluids within the tubes.

As shown in FIG. 5, the valve assembly 50 includes a motor 52 whichdrives rotation of a pinion 54 that mates with a rack 56. Rotation ofthe pinion 54 is translated into axial movement of the rack 56 in distal(lumen-closing) and proximal (lumen-opening) directions relative to amount block 58 with a pincher 60 coupled to a distal end of the rack 56.As the rack 56 is driven distally by the rotation of the pinion 54, thepincher 60 compresses a respective lumen in the cassette 28 against awall of the cassette 28. A position sensor 62 (e.g., an optical sensor,Hall effect sensor, etc.) may be included in the valve assembly 50 todetermine a position of the pincher 60 relative to the respective lumen.In this manner, an amount of closure of the respective lumen and/or anamount of fluid flow permitted through the respective lumen at theamount of closure may be determined. As will be described further below,the system 2 may utilize the closure information to adjust a volumeand/or pressure of fluid circulated through the uterus.

Referring back to FIG. 4, the valves 46 may include a number of valveassemblies 50 including similar rack and pinion assemblies and pinchercombinations or other mechanisms corresponding to a number of lumens inthe cassette 28 to be selectively opened and closed. The valvearrangement 40 may further include a safety valve 64 which closeswhenever a pressure within the lumen exceeds a predetermined maximumpressure or whenever an unsafe condition is detected.

The motor arrangement 42 includes a motor 66 (e.g., a DC brushlessmotor), a speed sensor 68 and an impeller coupling 70. Current suppliedto the motor 66 rotates an armature thereof which, in turn, rotates theimpeller coupling 70. In one exemplary embodiment, the impeller coupling70 includes one or more magnets which, when the cassette 28 is insertedinto the console 4, are magnetically coupled to one or more magnets onan impeller in the cassette 28 so that rotation of the impeller coupling70 rotates the impeller to drive fluid through the cassette 28 and intothe patient with no contact between fluid in the cassette 28 andcomponents of the console 4 outside the cassette 28. Those of skill inthe art will understand that the impeller coupling 70 and the impellerare an exemplary embodiment of any pump arrangement which may be used tooutput fluid from the cassette 28. The speed sensor 68 may be coupled tothe motor 66 to detect a rotational speed of the armature thereof todetermine, for example, a speed (and/or pressure) at which fluid isbeing circulated through the cassette 28 and/or the uterus.

As shown in FIG. 6, an exemplary embodiment of the front side 30 of theconsole 4 includes the user interface 12, the display screen 14 and thekeypad 16 which may be controlled by a user interface printed circuitboard (PCB) 70 which interprets user input entered via the keypad 16 anddisplays the content on the display screen 14. A screen cover 72 may beoverlaid on the display screen 14 to protect and allow cleansingthereof. The disposable overlay described above is preferably overlaidon the screen cover 72. A speaker 74 disposed within the console 4 maybe utilized to provide to the operator audible signals such as, forexample, voice instructions, warning signals, etc. which, when used inconjunction with the visual content presented on the display screen 14facilitate operation of the system 2. Additionally, the audible outputmay be useful when, for example, two persons are working in conjunctionto perform the ablation procedure. That is, the operator may bemonitoring operation of the system 2, while a physician and/or nurse maybe monitoring the fluid circulation through the uterus. The audibleoutput makes both persons aware of the progress of the ablationprocedure regardless their fields of view.

As shown in FIG. 7, the chassis 38 in the console 4 according to theexemplary embodiment is encased by the right, left, front and rear sides30, 32, 34, 36 of the housing 10. A power arrangement 76 mounted on thechassis 38 includes a power PCB 78, a toroid 80, a line filter 82 and apower supply 84 coupled to, for example, a port for receiving a linevoltage. For example, the power supply 84 may have a power cordextending therefrom to be plugged into a wall outlet, or the port mayreceive a plug as part of an extension cord. The line filter 82 treatsthe power to, for example, eliminate surges, harmonic transientcurrents, spikes, etc. in the current being delivered to the console 4.The filtered current is then transmitted to the power PCB 78 whichdistributes power to operational components of the system 2. The toroid80 operates as a transformer, providing electrical isolation betweencircuits in the console 4.

Also mounted on the chassis 38 is a motor controller 86 which receivesinstructions from a controller 44 to control operation of the motor 66.The controller 44, which is shown in FIG. 4, may be a central processingunit which coordinates operation of the system 2 during the ablationprocedure. That is, the controller 44 may process an instruction setstored in a memory for controlling the user interface 12, the motor 66,the valves 46, the safety valve 64, etc. during the ablation procedure.An exemplary use of the system 2 for performing an ablation procedurewill be explained in more detail below.

FIGS. 8 and 9 show an exemplary embodiment of the cassette 28 accordingto the present invention. As noted above, the cassette 28 may beembodied in a housing 88 sized and shaped to fit within the slot 26 onthe console 4. For example, the housing 88 may include rails along itssidewalls which are received by guides on the sidewalls of the slot 26,allowing the cassette 28 to slide thereinto. Once in the slot 26, thecassette 28 may be mechanically locked in place (e.g., latches, hooks,etc.), gravitationally held in the slot 26, magnetically coupled to theconsole 4, etc. In one exemplary embodiment, the instructions providedon the user interface 12 may instruct the operator on how and when toinsert and remove the cassette 28. The console 4 may lock the cassette28 in the slot 26 to prevent removal during an ablation procedure.

The fluid from the IV bag enters the cassette 28 via a fluid supplylumen 90 which terminates in a reservoir 92. In this embodiment, a levelsensing board 94 is disposed within the reservoir 92 for monitoring avolume of fluid therein. During the ablation procedure, the controller44 compares the volume to a predetermined volume (or range thereof) todetermine whether fluid has been lost/leaked. Based on the results ofthe comparison, the system 2 may shut down or execute a predeterminedsafety procedure. In the exemplary embodiment, the level sensing board94 comprises a plurality of level sensors (e.g., capacitors) arrangedalong a height of the board 94. By analyzing signals received from thelevel sensors, the controller 44 may determine the volume of the fluidwithin the reservoir 92.

The safety procedure may be one or more sets of instructions stored inone or more locations to create a redundant safety net. For example, aprimary safety system may be stored as a set of instructions forexecution by the controller 44 so that, when the controller 44 isalerted to any of a number of predefined faults, the controllerinitiates the safety procedure and puts the system into a safe state. Inaddition, a secondary safety system may be included in the form, forexample, of a separate non-volatile memory of a complex programmablelogic device (CPLD) coupled to the controller 44 to monitor a watchdogsignal therefrom. If a problem arises which compromises the integrity ofthe controller 44, the watchdog signal will be compromised as well andthe CPLD will put the system into the safe state. The safety proceduremay be executed if, for example, the controller 44 indicates that acomponent of the system 2 is non-responsive or otherwise malfunctioningwhile the secondary system (i.e., the CPLD) will put the system in thesafe state when the controller 44 malfunctions.

The fluid in the reservoir 92 is directed into a heating chamber 96 byan impeller 98 which, as described above, is rotated by the impellercoupling 70 in the console 4. As shown in FIGS. 14 and 15, an exemplaryembodiment of the impeller 98 includes a plurality of veins 160 disposedon a first surface and a plurality of magnets 162 disposed on a secondsurface. Each of the veins 160 may be formed as a concave projection onthe first surface and have a predefined spacing and angle relative toadjacent veins. In this configuration, the fluid interfacing with theimpeller 98 is forced from a center of rotation thereof and into theheating chamber 96. The magnets 162 may be embedded in the impeller 98having exposed surfaces flush with the second surface which magneticallycouple to the magnets on the impeller coupling 70. An interface betweenthe impeller 98 and the impeller coupling 70 may be configured so thatonly the first surface of the impeller 98 comes into contact with thefluid, while the second surface is exposed on (and/or forms a part of)an external surface of the cassette 28. Alternatively, the impeller 98may be fully enclosed within the cassette 28.

The heating chamber 96 includes a heating element 100 which heats thefluid therein. Operation of the heating element 100 may be based on atemperature measurement of the fluid obtained by a temperature sensor(e.g., thermistor) in the heating chamber 96. By monitoring thetemperature measurement, the controller 44 ensures that the fluidtemperature is within a predetermined range (e.g., a temperature hotenough to ablate tissue). Those of skill in the art will understand thatthe heating element 100 may further include a cooling element or bedeactivated when, for example, the ablation procedure has been completedand the remaining surface tissue in the uterus is to be allowed to cool.

As shown in FIG. 13, the heating chamber 96, in this embodiment, issubstantially cylindrical with a fluid inlet 150 at a lower end thereof.The inlet 150, which receives fluid pumped from the impeller 98, isdirected substantially tangential to the cylinder so that the fluidswirls around the heating chamber 96 and is heated by the heatingelement 100 as it rises to an outlet at the top of the cylinder. Theheating element 100 extends substantially along a longitudinal axis ofthe cylinder so that the fluid travels around the heating element 100 ina substantially helical path as it rises in the heating chamber 96,maximizing energy transfer to the fluid.

When the fluid exits the heating chamber 96 it has reached the desiredtemperature leaving the cassette 28 via a delivery lumen 102 to pass toan introducer which has been inserted into the uterus. The fluid is thencirculated through the uterus and returned to the cassette 28 via areturn lumen 104. The returned fluid is then passed through a filter 106to remove any tissue remnants, coagulated plasma, etc. and fed backthrough the impeller 98 into the heating chamber 96. By continuouslycirculating the returned fluid while monitoring any volumes of fluidadded/removed from the system 2, the controller 44 can detect changesfrom the initial fluid volume as described above to determine a volumeof fluid absorbed into the body. When the ablation procedure has beencompleted, the fluid is drained into the drainage bag via a drainagelumen 110.

Electrical signals generated by the temperature sensors in the heatingchamber 96 and the level sensors in the reservoir 12 are transferred tothe controller 44 via a communications circuit board 108 and digitized.The digitized signals are then converted into procedural data (e.g.,temperature data and volume data) which is analyzed by the controller 44to monitor the progress of the ablation procedure.

During progression of the ablation procedure, the controller 44configures alternative fluid flow paths through the cassette 28 byselectively controlling operation of the valves 46 to open and close thefluid flow lumens therein. FIG. 11 shows an open loop flow path usedduring priming and/or cooling stages of the ablation procedure. Forexample, the system primes by opening the supply valve 140 to permitfluid from the IV bag through the cassette 28 to the reservoir 92 andthrough the impeller 98 to the heating chamber 96 which is inactive atthis point through the safety valve 64 into a delivery (not shown) of anintroducer 112. The fluid exits the delivery lumen into the uterus andis drawn back from the uterus into a return lumen (not shown) of theintroducer 112 which passes the fluid back through the safety valve 64and out to a drainage bag via a drainage valve 142. When the system hasbeen primed, the valves of the cassette 28 are reconfigured to theclosed loop configuration of FIG. 12 for heating of the fluid andablation. Specifically, the drainage valve 142 is closed so that fluidcirculates from the reservoir 92, through the impeller 98 and theheating chamber 96 and into the uterus via the safety valve 64 and theintroducer 112. The fluid returning from the uterus via the return lumen104 of the introducer 112 passes through the safety valve 64 and thefilter 106 to return to the reservoir 92 via the middle valve 144 andcontinues to circulate through this path during the ablation procedure.In this configuration, the heating chamber 96 is active to raise thetemperature of the fluid to a desired level for ablation. In addition,in this configuration, the bypass valve 146 is opened when necessary tobleed off excess flow from the output from the heating chamber 96returning this bled-off fluid to the reservoir 92 without passingthrough the uterus. When the procedure has been completed, the drainagevalve 142 is opened and the bypass valve 146 and the middle valve 144are closed to return the system 100 to the open-loop configuration ofFIG. 11. The heating chamber 96 is deactivated at this point so thatfluid currently circulating in the cassette 28 flows through the uterusand passes through the drainage valve 142 to the drainage bag withoutfurther heating. After this fluid has been drained, fresh fluid from theIV bag is passed through the cassette 28 into the uterus atsubstantially room temperature to flow out into the drainage bag until adesired amount of cooling has been achieved.

As shown in FIG. 10, an introducer 112 according to an exemplaryembodiment of the present invention is coupled to the cassette 28 viatubes 103 and 105 to deliver fluid to the uterus and to return the fluidfrom the uterus to the cassette 28. The tubes 103, 105 are coupled todelivery and return lumens 102, 104, respectively, of the cassette 28and to fluid delivery and return lumens (not shown) within a sheath 113of the introducer 112. The fluid delivery and return lumens of theintroducer 112 terminate at respective openings at a distal end 118 ofthe sheath 113 which, when the introducer 112 is in an operativepositions, is located within the uterus. The introducer 112 mayoptionally include a vision system to allow visualization of theoperative area. Those of skill in the art will understand that thevision system may be substantially similar to the systems inconventional endoscopes (e.g., fiber optic or CCD-based systems).Alternatively, users may rely on the vision system of an endoscope orother instrument inserted through the introducer 112, as describedbelow.

The introducer 112 includes a grip 114 (e.g., an ergonomic handle)coupled to the sheath 113 and a scope connector 116 for receiving avisualization device, such as an endoscope. The grip 114 facilitatesholding and manipulation of the introducer 112 with a single hand whilethe operator uses his free hand to interface with the console 4, adjustthe visualization device, manipulate the patient's anatomy, etc. Thescope connector 116 according to this embodiment is disposed on aproximal end of the introducer 112 and provides an attachment point forthe visualization device (e.g., a hysteroscope, an endoscope) so thatthe visualization device may be passed distally through a visualizationlumen in the introducer 112 and extended out of the distal end 118.Thus, the operator may visually monitor insertion of the introducer 112into the uterus.

The scope connector 116 may comprise an optional locking ring 117 and ascope adapter 120 which allow the introducer 112 to be adjusted toaccommodate visualization devices of varying lengths. The visualizationdevice is inserted into the proximal end of the introducer 112 throughthe scope connector 116 and locked thereto using the locking ring 117.The user then depresses the scope adapter 120 releasing the scopeadapter 120 from a current locking aperture 121. This allows the scopeconnector 116 to slide proximally out of or distally into the introducer112 so that, when the visualization device has been inserted through thesheath 113 to a desired position in the uterus, the scope connector 116supports the portion of the visualization device extending out of theintroducer (e.g., a proximal end of an endoscope immediately distal ofthe control handle). Those of skill in the art will understand that thescope connector 116 may be implemented as any mechanism which allows thelength of the introducer 112 to be adjusted to and maintained at a newlength. For example, as shown in FIG. 10, the scope adapter 120 isformed as a projection on an outer surface of a distal portion of thescope connector 116 received in and movable between one of a number oflocking apertures 121 formed on the grip 114. Partial barriers may beformed between each of the locking apertures 121 to retain the scopeadapter 120 in a selected one of the locking apertures 121 maintaining aselected length of a portion of the scope connector 116 projecting fromthe proximal end of the introducer 112. In another embodiment, a rackmay be formed on the distal portion of the scope connector 116 matingwith a gear in the grip 114 so that rotation of the gear extends andwithdraws the scope connector 116 relative to the grip 114. A ratchetmay be provided to maintain the gear in a fixed position relative to therack, thereby maintaining the desired position of the scope connector116 relative to the grip 114.

The grip 114 may further include an optional tenaculum stabilizer 122.For example, during the ablation procedure, a tenaculum may be employedaround the cervix to enhance the seal of the cervix around the sheath113 of the introducer 112. A tenaculum that has been clamped around thecervix may then be coupled to the introducer 112 to ensure that theintroducer 112 remains at a desired position within the uterus and isnot inadvertently withdrawn therefrom. That is, it is important to makesure that the distal end of the sheath 113 is not withdrawn proximallyfrom the uterus during the procedure or non-targeted tissue will beexposed to the ablation fluid. Thus, a portion of the tenaculum ispassed over the tenaculum stabilizer 122 preventing movement of thesheath 113 proximally relative to the tenaculum. That is, once atenaculum has been locked in position on tissue, the tenaculum can beslipped over the tenaculum stabilizer 122. The tenaculum stabilizer 122is moved to a proximal-most position permitted by the tenaculum.Specifically, in the exemplary embodiment, the tenaculum stabilizer 122includes a fin slidably mounted on a rail 124 formed on the grip 114.The fin includes a hook which may receive finger grips or a crossbar ofa tenaculum as would be understood by those skilled in the art. When thetenaculum is coupled to the tenaculum stabilizer 122, the operatorselects a tension to be applied between the tenaculum and the introducer112 by moving the fin along the rail 124. A positioning mechanism (e.g.,ratchet, latch, clip, etc.) may be used to maintain a position of thefin relative to the rail 124, as would be understood by those skilled inthe art. Such a tenaculum stabilizer device is described in a U.S.Patent Application Ser. No. 60/971,409, entitled TENACULUM STABILIZERDEVICE, naming as inventors Christopher L. Oskin, Brian MacLean, StephenKeaney, Jozef Slanda and Jeffrey Zerfas filed Sep. 11, 2007. The entiredisclosure of this application is hereby incorporated by referenceherein.

The introducer 112 may further include an optional cervical seal 126separated from a distal end of the sheath 113 by a distance selected toensure that, when the distal end of the sheath 113 is in a desiredposition within the uterus, the seal 126 is located within the cervixproximal to the cervical os C. When the distal end 118 of the introducer112 is introduced into the uterus, the elasticity of the cervix providesa substantially fluid-tight seal around the sheath 113. However, tominimize the risk of ablation fluid escaping through the cervix todamage non-targeted tissue, the fluid-tight seal may beenhanced/maintained using the cervical seal 126. In the exemplaryembodiment, the cervical seal 126 is formed as a flexible membrane 127which overlies a wire mesh 129, a proximal end of which abuts a distalend of an expander member 130. A distal end of the cervical seal 126 isfixed to the sheath 113 while a proximal end is slidable along thesheath 113.

A seal actuator 128 comprises a ring rotatably mounted on the sheath 113and coupled to the expander member 130 which, in this embodiment, isformed as an oversheath telescopically mounted over the sheath 113. Thering may be coupled to the oversheath in such a manner that rotation ofthe ring moves the oversheath proximally and distally over the sheath113. For example, an outer portion of the proximal end of the oversheathmay be threaded to mate with threads on an inner portion of the ring ofthe seal actuator 128 so that, when the ring is rotated in a firstdirection, the expander member 130 slides distally along the sheath 113pushing the proximal end of the mesh 129 distally causing the cervicalseal 126 to expand radially away from the sheath 113.

As shown in FIG. 16, it is preferable that expansion of the cervicalseal 126 is executed when it is within the cervix proximal of thecervical os C so that none of the targeted tissue is covered by the seal126. In the exemplary embodiment, the sheath 113 is moved distally untilthe distal end 118 thereof is within the uterus. The sheath 113 is thenwithdrawn proximally to minimize a projection of the sheath 113 into theuterus maximizing a field of view of the vision system. While in thisposition, the cervical seal 126 is positioned entirely within the cervixwith a distal end of the seal 126 proximal of the cervical os C. Theexpander member 130 engages the proximal end of the cervical seal 126and pushes the proximal end distally along the sheath 113 into theexpanded position shown in FIG. 16. In the expanded position, themembrane 127 substantially engages an inner wall of the cervix enhancingthe seal provided by the natural resilience of the wall of the cervix.The distance between the distal end 118 and the distal end of thecervical seal 126 is preferably between 0 and 1.5 cm which the seal isactuated. A seal 126 according to an exemplary embodiment of theinvention may extend from a proximal end approximately 5 cm from thedistal end 118 with a maximum diameter of the seal 126 corresponding toa distance of 1.5 cm from the distal end 118.

Rotation of the ring in a second direction withdraws the expander member130, allowing the cervical seal 126 to return to its unexpanded statethrough the bias of the mesh 128 which tends toward the unexpandedstate. Alternatively, the proximal end of the mesh 129 may be coupled tothe distal end of the expander member 130 so that, as the expandermember 130 is moved proximally, the mesh 129 is drawn back into theunexpanded state against a bias of the mesh 128 which tends to expandthe seal 126.

In an exemplary use, the system 2 according to the present invention maybe used to ablate the endometrial lining of the uterus. When the console4 is activated, the display screen 14 may show (and the speaker 74 mayprovide) a pre-operative instruction set. For example, the instructionset may prompt the operator to hang the IV bag and the drainage bag. Thecontroller 44 may then detect whether the cassette 28 has been insertedinto the slot 26 and provide instructions regarding a procedure forconnecting the cassette 28 to the IV bag, the drainage bag and theintroducer 112. In addition, the controller 44 may determine, upondetecting the presence of the cassette 28, whether the cassette 28 hasbeen previously used and prevent operation or take other pre-ordainedsteps if prior use is detected.

The pre-operative instruction set may also instruct the operator toadjust a height of the console 4 to be substantially equal with a heightof the uterus or to achieve some other desired relationship between theheight of the console 4 and that of the uterus. In the exemplaryembodiment, the height of the console 4 is varied by adjusting the stand8 using a light beam (e.g., laser) emitted from the beam exit port 24 toensure that the console 4 is level with the uterus. When the console 4is level with the uterus, the operator may initiate the ablationprocedure by inserting the introducer 112 into the uterus via the cervixand expanding the cervical seal 126 within the cervix. The controller 44may then configure the cassette 28 for the open loop flow path byopening the fluid supply and drainage valves 140, 142 and circulate apre-operative fluid through the uterus, priming the endometrial liningfor ablation.

During a heating stage of the ablation procedure, the fluid from the IVbag enters the cassette 28 and is heated to a predetermined temperature(e.g., approximately 85-90□C) as indicated by signals generated by thetemperature sensors in the heating chamber 96 and transferred to thecontroller 44 in the console 4 via the communications board 108. Thesignals may be digitized and analyzed to determine when the fluid hasreached the predetermined temperature. Prior to the fluid being heated,the controller 44 configures the cassette 28 for the closed loop flowpath by closing the fluid supply and drainage valves 140, 142 andopening the middle valve 144 so that fluid returning from the uterus isfed back into the reservoir 92, as described above.

When the fluid has reached the predetermined temperature, the console 4initiates a treatment stage circulating the heated fluid through theintroducer 112 into the uterus to ablate the endometrial lining asdescribed above in regard to FIG. 12. The heated fluid is delivered tothe uterus via the delivery lumen in the sheath 113, removed from theuterus via the removal lumen in the sheath 113 and returned to theconsole 4 where it is filtered by the filter 106 and returned to becirculated through the uterus for a predetermined duration (e.g.,approximately 10 minutes) to ablate the endometrial lining. Thetreatment stage may further include a cooling cycle in which the heatedfluid is allowed to cool and then circulated through the uterus toabsorb heat from the exposed tissue aiding in the healing process. Whenthe treatment stage has been completed, the console 4 employs a draincycle, emptying the fluid in the system into the drainage bag.

Those of skill in the art will understand that various hardware andsoftware-based variations may be implemented in the system 5 accordingto the present invention. For example, the height-adjusting mechanism onthe stand 8 may be controlled by position data generated by a positionsensor on the introducer 112. After the introducer 112 has been insertedinto the uterus, the position data may be analyzed to determined aheight of the introducer above the floor. If the height of the console 4is not properly aligned with the height of the introducer 112, an alarmmay be activated or an automatic height adjusting mechanism may adjustthe height of the console 4 to the desired level. In addition, apressure transducer may be coupled to the distal end 118 of theintroducer 112 to sense the fluid pressure within the uterus. Thepressure transducer may provide pressure data to the controller 44 whichdetermines whether the pressure is within a predefined operable range,and if the pressure is outside of the range, the controller 44 mayexecute a safety procedure.

The present invention has been described with reference to specificexemplary embodiments. Those skilled in the art will understand thatchanges may be made in details, particularly in matters of shape, size,material and arrangement of parts. For example, the invention is notlimited to methods and devices for the thermal ablation of the uterinelining. Accordingly, various modifications and changes may be made tothe embodiments. The specifications and drawings are, therefore, to beregarded in an illustrative rather than a restrictive sense.

1. A thermal ablation system comprising: a fluid handling unit receivingfluid from a fluid source at a first pressure, the fluid handling unitincluding a heater heating the fluid to a desired temperature and apump; and an introducer including a sheath which, when in an operativeposition, is received within a hollow organ, the sheath including adelivery lumen introducing fluid heated by the heater to the holloworgan and a return lumen withdrawing fluid from the hollow organ andreturning the withdrawn fluid to the console via a return lumens whereinthe pump increases a pressure of the fluid between the fluid source andthe delivery lumen of the introducer.
 2. The system according to claim1, wherein the fluid handling unit includes a reusable console and adisposable cartridge.
 3. The system according to claim 1, wherein thepump increases the pressure of the fluid by a substantially constantamount.
 4. The system according to claim 2, wherein a motor of the pumpis located in the console and an impeller of the pump is located withinthe cartridge.
 5. The system according to claim 4, wherein the motordrives the impeller via a magnetic coupling.
 6. The system according toclaim 2, wherein no fluid passes through the console.
 7. The systemaccording to claim 1 wherein the fluid handling unit is mounted on avariable height base.
 8. The system according to claim 3, wherein theconsole includes a fluid bag mounting pole for mounting the fluid sourcea predetermined height above a fluid inlet of the fluid handling unit toachieve a desired substantially constant fluid pressure within thehollow organ.
 9. The system according to claim 1, wherein the fluidhandling unit includes a user interface including at least one of adisplay screen, a touch screen, a keypad and a speaker.
 10. The systemaccording to claim 1, wherein the fluid handling unit includes a heightdetermining mechanism ensuring a desired height differential between thefluid source and the hollow organ.
 11. The system according to claim 10,wherein the height determining mechanism provides a visual indication ofa reference height relative to the hollow organ.
 12. The systemaccording to claim 11, wherein the height determining mechanism includesa light beam port projecting a light beam substantially horizontally.13. The system according to claim 2, wherein the console includes avalve arrangement selectively opening and closing fluid circulationlumens in the cartridge.
 14. The system according to claim 14, whereinthe valve arrangement includes at least one pincher valve.
 15. Thesystem according to claim 2, wherein the cartridge includes a filterarrangement filtering the fluid from the return lumen.
 16. The systemaccording to claim 2, wherein the cassette includes a reservoir storingthe fluid and a level sensor outputting a signal corresponding to alevel of the fluid within the reservoir.
 17. The system according toclaim 16, wherein the console includes a controller determining a fluidvolume as a function of the signal.
 18. The system according to claim 2,wherein the cartridge includes a drainage lumen emptying fluid from thereturn lumen into a drainage bag.
 19. The system according to claim 1,wherein the introducer includes a grip having a sheath extendingdistally therefrom and a scope connector extending proximally therefrom.20. The system according to claim 19, wherein the grip is sized andshaped for single-handed use.
 21. The system according to claim 19,wherein the scope connector includes a lock for detachably coupling avisualization device to the introducer and a scope adapter adjusting alength of the introducer.
 22. The system according to claim 19, whereinthe sheath includes a seal disposed proximally of a distal end of thesheath.
 23. The system according to claim 22, wherein the seal isradially expandable from the sheath.
 24. The system according to claim22, wherein a distance between the distal end of the sheath and a distalend of the seal is selected so that, when the distal end of the sheathis in a desired position within the hollow organ, the seal is locatedwithin a lumen through which the sheath is introduced into the holloworgan.
 25. The system according to claim 24, wherein the hollow organ isa uterus and the distance is between 0 cm and 1.5 cm so that, when thedistal end of the sheath is in a desired position within the uterus, theseal is located within a cervix.
 26. The system according to claim 1,wherein the introducer includes a tenaculum stabilizer.
 27. A method,comprising: aligning a fluid handling unit of a thermal ablation systemto a desired height relative to a hollow organ to be treated; heating afluid in the fluid handling unit to a predetermined temperature; pumpingthe fluid from the fluid handling unit via a fluid delivery lumen intoan introducer inserted into the hollow organ; and after the fluid hasbeen circulated through the hollow organ, withdrawing the fluid from thetissue structure to the fluid handling unit via a fluid return lumen inthe introducer.
 28. The method according to claim 27, furthercomprising: filtering the fluid received from the fluid return lumen;and pumping the fluid back into the introducer via the fluid deliverylumen.
 29. The method according to claim 27, further comprising:monitoring a volume of the fluid circulating through the hollow organ;and when the volume is outside a predetermined range, executing a safetyprocedure.